


Message In A Bottle

by Trovia



Category: Battlestar Galactica (2003), Harry Potter - J. K. Rowling
Genre: Action/Adventure, Community: xover_exchange, Crossover, Gen, Time Loop, Time Travel
Language: English
Status: Completed
Published: 2010-12-09
Updated: 2010-12-09
Packaged: 2017-10-13 14:29:03
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,346
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/138383
Author URL: https://archiveofourown.org/users/Trovia/pseuds/Trovia
Summary: <blockquote class="userstuff">
              <p>Severus Snape receives a message from the future. It’s about Kara Thrace falling out of the sky. It's <i>not</i> about Felix Gaeta charming a jump drive, though God knows Tonks wishes it was.</p>
            </blockquote>





	Message In A Bottle

**Author's Note:**

  * For [sentientcitizen](https://archiveofourown.org/users/sentientcitizen/gifts).



A great many important events in the Wizarding world had been heralded by smelly explosions and loud banging noises. It was no different this time around.

In the case of one Severus Snape, said explosion happened when the door to his private rooms was swinging open after he had muttered the appropriate incantation.

Grass-green and purple and golden sparks had exploded in the doorframe. Smoke was suddenly everywhere, the strong smell of roasted frog eyes and brimstone assaulting his nose. A terrible laugh seemed to hang in the air - he was reminded of Bellatrix so strongly he shuddered, until noticing it had just been an especially loud magic screech.

Severus’ first reaction was to hiss, reaching for his wand with instincts honed by war.

The potions teacher knew immediately that this couldn't be a prank. Apart from the fact that he had just seen the Potter brat in class sprouting _no_ warts, his rooms were also hidden deep in the guts of the castle. It was unlikely that a pupil would have known to hop around the statue of Pansy the Pointless - thrice - while muttering Salazar Slytherin's most beloved blood pudding recipe.

But the smoke dispersed within seconds, as if inviting him into his perfectly untouched bedroom. Even the sparks had died before reaching the ground. All in all, it was a rather undramatic affair. The smell lasted for only a moment longer, colouring with almond and giving unsubtle hints to the expert observer that magic of time had been in play.

The only thing left behind was a piece of parchment, neatly coiled up at the foot of the rug. When Severus carefully stepped up to it, turning it around for a closer look with a wave of his wand, he made out what seemed to be a signature, signing a letter. Two signatures, to be precise. One of them was his own.

And while it seemed a more experienced and more mature hand than what he was used to, Severus had read enough of Granger’s essays to recognize her handwriting as well. He still didn't know what had happened, but he didn't need to. The hints were clearly pointing to something he’d despise.

Severus smirked in disgust of the universe itself.

* * *

 _Just trust yourself._

Those had been Moody’s last words of wisdom just before she’d boarded the Viper, the same thing he’d always taught his recruits in training. _Trust yourselves. Aurors who don’t trust their guts are dead._

Fat load of luck it had brought her, but unfortunately, it was the only bit of wisdom Tonks had left. She straightened her back, whisking a cynical grimace out of her face by sheer power of will to replace it with the friendly smile of round-faced Amanda Scyberra, whose body was currently hers.

“Wotcha, Gaeta,” she said cheerfully, dropping down on the chair on his bedside. Her wand was already pointing at the curtains. “ _Silencio._ ” She beamed at him. “Getting better?”

Lt. Gaeta looked... sick. It made her stomach lurch, that was how sick he looked. Yesterday’s fever had broken, but sweat was still covering his forehead, and she refused to look at his hand almost clutching the remains of his leg. The leg he’d lost because of her.

Except he didn’t know that, because she’d been impersonating a different person at the time.

Gaeta managed a smirk. “Best time of my life.” His voice was hoarse. “I’ll take care of the music if you bring on the strippers, and we’ll party.”

It had been her gut that had told her to look for a dead witch from the Scylla that Gaeta had known on New Caprica - any excuse was a good excuse to run into him in sickbay by accident. Her regular persona wouldn’t have allowed her to come visit him. Even if she could make people believe that Kara Thrace had an interest in Gaeta’s recovery, which she couldn’t, Gaeta still wouldn’t have let Thrace anywhere near him. And why should he? She’d cost him his _leg_.

Tonks’ stomach clenched.

“Good for you to look at the bright sight,” she chirped with an effort. “Look, I brought Cackling Candy, too.”

She raised a small box of the Colonists’ equivalent of Chocolate Frogs. On better days, she thought they were quite wonderful - easy enough to transfigure out of algae, and they changed the tune of cackling while you chewed on them. They made her miss home all the more.

“You shouldn't have.” But Gaeta's sickly face showed longing. He couldn't do magic, of course, while he was stuck in sickbay. From what he’d told her on former visits, it was even hidden in his locker most of the time, if he didn’t need it at work. Galactica was an old ship, he’d said - people had said it was a miracle that she could still fly, when truly it was just a matter of a dozen magic officers speaking maintenance charms excessively. But most of the crew were Muggles; Gaeta glanced at the curtain in worry. “What if people can hear?”

Tonks shrugged. “That's what the Silencing charm was for. And you know Ishay won't tell on us.” Opening the box, she waved it at him more eagerly than she felt. “Dig in. You need the strength. It’s so much better than that Muggle grub.”

She’d known he wouldn’t refuse. Nobody in this Fleet ever said no to food - either out of real hunger or out of an appetite for food that _tasted_ like something. That made Tonks long for home, too, for her own body instead of Amanda Scyberra’s and Kara Thrace’s, two women whose bodies she could borrow because they were _dead_.

Gaeta was chewing on a candy bar gingerly, checking with his eyes to make sure the Silencing charm was truly working before daring a sickly small bite.

The first time Tonks had noticed Gaeta had been in the community showers - and good god, those still made her blush. He’d been the first wizard she had spotted in the Fleet. Arithmancy masters on Earth might not have the degree tattooed on their back, but a magic symbol was a magic symbol everywhere.

Of course, that had been before Tonks took command of the Demetrius and made complete bollocks of it all.

That’s what she’d gotten for going with her gut, impersonating a woman she knew nothing about. Leoben had told her he _loved_ her, and it had been so clear that Thrace had been sleeping with somebody not Sam. As it had just grown glaringly obvious, Leoben hadn’t been it. So Tonks couldn’t even _blame_ her crew for having mutinied. It had all gone so wrong. Gaeta was just the only victim out of three to have lived to tell the tale.

Watching him eat, Tonks’ smile vanished. The Portkey was safe, if deactivated, in her pocket at all times. She could feel it poking at her lower ribs even now.

* * *

It had taken days to bring the potions kitchen of Grimmauld Place into any sort of usable shape again. Buried deep in a cellar that even Kreacher seemed hesistant to enter, it had been covered with spider webs as thick as curtains, some of them jumping at visitors and shooting little pink darts into their ears. Even Sirius claimed to never have entered it; the entrance had been found childproofed with a curse that spookily resembled _Cruciatus_.

Remus had to suppress a shudder when he thought about it. It didn’t help that Severus, unaware of the observers, was moving along the shelves embedded in the ancient walls, choosing ingredients, with the obliviousness of a wizard utterly in his element. The room was sound proof, of course. Neither he nor young Hermione Granger, stirring their concoction in the cauldron, could hear anything they were saying. The young witch’s face was scrunched in concentration, chasing away her former anxiety. Remus had thought it amusing that she had been more nervous about attempting advanced magic than about working with a professor who disliked her.

“I still think it has to be some sort of cock up,” a voice remarked behind him. Turning from where he was leaning in the doorframe, Remus saw Sirius had shown up, a deep scowl on his forehead. “Granted, I can’t make out how it could be. I wouldn’t trust any message Snape alone sent us from the future, naturally. But Snape and Hermione both?” He shook his head.

Remus shrugged. “I imagine that is why they signed it together.” He could hardly blame his friend for being sceptical - he was as well, they all had been. “Have you looked at some of the charm work described in that message, though? I’d quite easily imagine that Hermione could invent it in the future. It has her style all over it. Snape’s, too. They seem to have worked it out together.”

Sirius gave him a look. “You realize that only makes it creepier?”

Years of mutual hate in Hogwarts won over maturity for a moment: Remus chuckled.

But Sirius was returning to the topic at hand. “I admit I wouldn’t have believed a thing about it,” he said more seriously than before. “A fleet of alien Muggles flying towards us? Come on. Even if it was true, what in the world should it have to do with us?” _We have more important problems at hand,_ was what he didn’t have to say. Voldemort still hadn’t made his move. “But when this Kara Thrace fell out of the sky... and the things she said before she died...”

Remus couldn’t help but agree. Neither man had been there to see when the stranger crashlanded in the Cotswolds, but both of them had witnessed how she had been admitted to St. Mungo’s from Kingsley’s point of view in a Pensieve. The woman in her Muggle vehicle had Apparated into the sky out of nowhere - spontaneous magic in the face of death, they thought. She had been burned badly in the crash, dying just a day later.

But the things she had told them before it was over... Wizards hiding in a fleet that had survived a Muggle war. Muggles so powerful that they’d created life out of machines - deadly life come to kill wizards and Muggles alike.

They wouldn’t have been able to believe it, if Snape and Hermione’s message hadn’t warned them it would happen.

“Well,” Sirius eventually said. “I guess it’s going to be done with soon enough.” He nodded at the potions kitchen, Snape and Hermione moving silently from cauldron to cauldron, following instructions written by themselves. “The illusion will soon be in place. All those Muggles will see of Earth will be a muddy wasteland. And they’ll fly on.”

“Let’s hope they will.” Remus couldn’t help the feeling of discomfort overcoming him when thinking of the one thing they hadn’t discussed. “I’m more concerned about what’s happening up there right now...”

He could see Sirius looking at him in the corner of his eye. “She’ll be alright, Moony.” A strong hand was placed on his shoulder, squeezing it reassuringly. “She’ll use the Portkey and come back, and be alright.”

Taking a shuddering breath, Remus nodded. He just hoped it would be true.

* * *

“Starbuck!” Adama ground out. “Jump the ship!”

“I don’t have the rendezvous coordinates!”

“Doesn’t matter! Just jump us out of here now!”

And Tonks was already at the console - Gaeta’s console except Gaeta was dead, thousands of tons of metal shaking around her and threatening to fall apart - like the world was dying. She was dirty, she was hurting - she’d probably broken a rib somewhere out there. It was hard not to grimace, easy to let the identity of the woman she’d been impersonating wash over her like a second skin.

 _Frak, Gaeta. Why did that frakker have to die?_

Because she wasn’t a Colonist. She wasn’t a Colonist witch and she wasn’t a pilot, and she had _no fucking clue_ what she was doing right now. She just knew the console was _brimming_ with magic underneath her fingertips, aching to be charmed back into shape by the hand that had tended to it for so long.

Bad enough that she had screwed it up. Bad enough that she screwed it all up on the Demetrius when no one had _told_ who or what that Leoben even was--

 _“I look at you now, I don't see Kara Thrace, I see an angel...” Frak it._

\--getting a man shot and a woman killed, just for Sam to be shot - who she had grown to _like_ \- in that frakking useless mutiny, frakking Gaeta losing hope...

“There must be...” she breathed. “There must be some kind of way out of here...”

Why the fuck had she had to follow the instructions - she shouldn’t have waited so long, waiting for Galactica to jump far enough away from Earth to keep her _other_ people safe - she should have executed that jump sooner, she shouldn’t have waited until Gaeta was dead and couldn’t help her with this Muggle shit anymore...

Tonks was breathing hard. All she could think was that those people had been her people for six months - all she could think was that they would _die_ if she didn’t bring them to safety somewhere...

She didn’t know any coordinates. All she knew was some Arithmancy, and the charms she’d been given by Snape, and the fact that spontaneous magic worked in danger even if you didn’t know what you were doing.

 _Home. These people need a home._

 _Just trust yourself._

Grimacing - hanging on to the decision and sticking with it like Moody had taught her - she punched in the numbers and she held on to the console, and just _shot_ a burst of magic through her palms into the ship because it had worked for Gaeta and...

 _Bring them home._

“Jump!”

The world lurched.

* * *

Harry was staring at the fireplace, glum as he always seemed to be these days. Hermione was watching him gingerly across the potions textbook in her lap. It had been exciting to spend her weekends at Grimmauld Place, creating charms and brewing potions that should be far beyond the reach of a fifth year if it wasn’t for the fact that _she had been the one to invent them_. But it was also good to be back at the Gryffindor common room - to be home.

Of course, it hadn’t exactly raised Harry’s spirit to know she was off to attend to Order’s business - something like it, in any case - getting to say hello to Sirius when he couldn’t. If she had come to think of the exciting conversations to be had when thinking of Professor Snape instead of far less pleasant things, that was neither here nor there.

On the upside, it was good to be able to talk to somebody about all the things that still troubled her with the charm work. There hadn’t been a word on Tonks for months now, and Hermione needn’t have remembered third year to know that the magic of time was dangerous. Hard to control for the best witch, prone to messy accidents, and dangerous.

Basically, she thought with a smirk, like all her life since she had first come to Hogwarts.

“The problem is,” she said, picking up the conversation again, “that we might never learn how Snape and I came - would come - to work on the illusion charm together.”

Harry knitted his eyebrows together. It seemed he was grateful for the distraction. “What do you mean?”

Hermione shrugged. She made sure to look around carefully before she spoke on in a low voice, but the only students close by where some second years engrossed in a loud and gory game of chess. “Think about it,” she answered. “At the beginning, Snape and I would come to work on those charms for some reason and we would send a message back to ourselves so we could use them in the past - the present,” she corrected herself with a frown. “But we’re in a time loop already, aren’t we? This version of Professor Snape and me doesn’t have a reason to reinvent the charms. We already _have_ the charms. All we’ll have to do is wait out Tonks’ return to make sure it all worked out, and send them back into the past in the original letter.”

It just came to show again that Harry could be a brilliant student if he just put his mind away from the war for a moment - or from Quidditch, at that - when he just leaned back, taking that one in without even blinking. Then his eyes darkened. “Except if Tonks doesn’t come back,” he muttered. “Have you ever thought of that?”

Shuddering, Hermione looked down. Truth was, she had. She’d woken up more than one night covered in sweat from dreams of Tonks coming back dead - or not coming back at all - or coming back _wrong_. She’d pictured years and years of frantically trying to optimize the charms, doing it all again and sending back _new_ instructions, better instructions, instructions that would prevent their planet from getting involved in another useless war _and_ spare the Auror’s life.

Maybe that’s why they had - would have - sent the message back into the past in the first place. Maybe the robots had come and they had tried to save them all - maybe then they’d sent Tonks and it hadn’t worked out either - maybe then they’d worked it out all again... It didn’t bear thinking about.

Harry must have gathered what was troubling her, because when she looked up again, he was leaning closer.

“There’s an upside to it, too, you know?” His eyes were twinkling with a new - dark and desperate - kind of humour that still made her pause.

She frowned. “What is it?”

Harry smirked. “It means there’s a future where you and Snape had time to spend years on creating the charms,” he said. “That must mean Voldemort wouldn’t have been there to distract you, would he?”

Hermione couldn’t help it; she stifled a chuckle. Not because it had been a particularly _funny_ thing to say - it was anything but. It was because that was an observation which immediately made sense. And because the idea of a world without Voldemort had become so absurd in the last couple of weeks that no other way of handling that unexpected sparkle of hope did occur.

* * *

Hope. Home. _Peace_.

Lee breathed in - fresh, clean, _new_ air, filling his lungs - and it was _warm_ and there was _sun_ and it was _over_... - he wanted to laugh, just because.

“I want to explore,” he said, eyes shining. It was like reciting. “I want to climb the mountains. I wanna cross the oceans, I wanna...” Now he laughed, for real. _So much air._ “Gods, I can’t believe I’m saying this. It sounds so exhausting... - I must be cra...”

He turned around, finding himself the only person as far as he could see.

Kara was gone.

* * *

By default, Aurors were intimidating people. Spending half a year impersonating Kara Thrace hadn’t helped transform Nymphadora Tonks into an entirely unobtrusive person, either. Her palms hit the kitchen chair of 12 Grimmauld Place with a bang, and her face would have made lesser people quiver.

“I don’t give a toss if the Dark Lord is waiting for you to come back,” she snapped. “This is more important. This is _now._ These people _trusted_ me. I don’t care what I was sent to do - I meant to send them into _safety_. Now, how about you to get off your pale potion brewing arse for a change, and repair the bloody damage.”

Unfortunately, Severus was none of the before-mentioned lesser people.

And angry do-gooders just made him smirk. “I thought your actions solved the problem rather thoroughly,” he said, not bothering to hide his spite. “Professor Dumbledore agrees. Your Muggle Fleet is gone. There is no way for them to come back, so we can go back to fighting the _real_ war. Let the strangers be. I understand they will be busy reinventing civilized life for quite some time.”

Tonks pressed her lips together. “They’re caught in the _past_ , Snape. They’re in a fra... a fucking time loop now. The charms you gave me went wrong. They interacted with the navigator’s charms the wrong way.”

Severus snorted. It was hardly his fault - or Granger’s at that - if their magic was corrupted by the charm work of a wizard they hadn’t even known existed. No matter that he’d meddled with the Muggle technology that had brought doom upon all those people in the first place, as far as Snape had bothered listening to Tonks’ report. He didn’t know why they should care, either.

There was a war going on out there. Voldemort had attacked Azkaban just days ago, taking along not only his most devoted and most dangerous followers including dear Bellatrix, but also every Dementor to have ever served the Ministry.

His lips twitched in distaste. “I’m surprised you’re caring so much, _Nymphadora_. I would have thought an Auror of all people would be able to prioritize.”

Tonks looked at him as if he was bonkers.

It looked like she had a hard time loosening her grip on the table, relaxing her face by sheer force of will.

After a pause, she looked away, saying, “We threw them into a time loop, Snape. A big one. I’m surprised it was even possible for me to Portkey out of it. You haven’t been up there, you can’t understand - but all that pain and death up there... It can’t just happen again and again. It just can’t.” She shuddered, giving him an imploring look. Snape noted with fascination that her eye colour had shifted into a dark brown - the Blacks’ eye colour, her true one. “I don’t care how long it takes you and Hermione to reinvent the charms,” she said. “I wrote down all I know about Gaeta’s maintenance magic. You have to figure out the right way to do it, and send a better message back in time this time around. Until you get it right.”

All that pain and death up there - of course, he wouldn’t be expected to understand anything about that, seeing as Death Eaters couldn’t possibly be able to feel empathy. Secretly, Severus shuddered just a little, thinking of victims who’d crawled up to him through Cruciatus pain to beg for mercy, good people dying on both sides... - Lily’s hair red as blood, fanned out on a battered rug, fourteen years ago the morning after Halloween. There were pictures that would always haunt him - even him. He’d rather die than admit it, but he _could_ imagine what Tonks had gone through when hiding amongst the enemy, pretending to be one of them. It was easy to forget the side you were on.

The irony was that Tonks’ magic had worked perfectly well out there. She had been trying to send those people to a home, after all, and that was exactly what had happened - the magic hadn’t so much sent them to a new home, but rather an _old_ one - to their place of origin.

He kept his face blank when he held out his hand. “Your notes.”

Tonks searched his face. She seemed older than she had before. Battle-worn. An expression you would look for if you wanted to identify the first war veterans. “Thank you,” she said.

Time magic was such a tricky and powerful thing, Severus mused when the Auror left, leaving him alone in the kitchen with a piece of parchment in his hands. It was almost impossible to do it right - it was truly astonishing to think that in some future in some world that didn’t exist anymore, Granger and he had invested years developing the charms necessary to fool a whole population. He wondered how often this very day had repeated in this time loop they’d created for themselves - how many Tonkses had met him in this kitchen already, telling him to make it right.

He wondered idly, for a moment, how many Snapes before him had promised her to do so before pointing his wand at the piece of parchment and saying, “ _Evanesco._ ” It was gone a moment later, without sound. It was better to never even read it.

Severus was almost sorry that he and Granger would never start working on the charms. But why should they when they already had a solution that worked? It wasn’t Tonks’ to decide it wasn’t enough to make it work, it also had to be _comfortable_.

Nothing had ever been comfortable for _him_. He’d sworn an oath to protect a different people already.

Everything that had happened before would happen again, yes - for the ‘Colonials’ as well as for them. And after that, there was a Dark Lord waiting for him.  


* * *

Grass-green and purple and golden sparks had exploded in the doorframe. Smoke was suddenly everywhere, the strong smell of roasted frog eyes and brimstone assaulting his nose. Severus’ first reaction was to hiss, reaching for his wand with instincts honed by war.

He knew immediately that this couldn't be a prank. Apart from the fact that he had just seen the Potter brat in class sprouting _no_ warts, his rooms were also hidden deep in the guts of the castle. It was unlikely that a pupil would have known to hop around the statue of Pansy the Pointless while muttering the correct blood pudding recipe.

But the smoke dispersed within seconds. The only thing left behind was a piece of parchment, neatly coiled up at the foot of the rug. When Severus carefully stepped up to it, turning it around for a closer look with a wave of his wand, he made out what seemed to be a signature. No - two signatures.

One of them was his own. And Severus had read enough of Granger’s essays to recognize her handwriting as well. He still didn't know what had happened, but he didn't need to. Clearly it was something he’d despise.

Severus smirked in disgust of the universe itself.


End file.
